Database Reference
In-Depth Information
By inspecting the I/O throughput and then comparing it to the PGA, you can also pinpoint when sorting and
hashing may occur within the PGA and when it may “swap” to temp, (causing higher I/O due to temp tablespace
reads/writes).
The final section, shown in Figure
9-41
, displays specific temp usage. For DSS and OLAP environments, knowing
temp usage can be very helpful. The SQL Monitor displays this in the SQL Monitor detail report.
Figure 9-41.
Temp usage from the SQL Monitor report, displayed in a graph
Using these specific SQL Monitor graphs offers high-level images detailing valuable usage areas outside of just
monitoring database activity from the SQL perspective. Whereas an administrator might query over a period of time
any of these areas or a combination of them, SQL Monitor is always available and clearly graphs out the recent usage
for each.
SQL Performance
The SQL submenu within the database target home page has numerous options, including these:
•
SQL Performance Analyzer
•
SQL Access Advisor
•
SQL Tuning Advisor
•
SQL Tuning Sets
•
SQL Plan Control
•
Optimizer Statistics
SQL Performance Analyzer
The SQL Performance Analyzer, although easily accessible through the Performance drop-down, is part of the Advisor
Central provision of EM12c features. The Analyzer provides a simple wizard to test and analyze how changes to a
database environment will affect a SQL tuning set.
This enables you to test the following in a session-level environment, without affecting users:
•
Changes in version compatibility
•
Parameter changes
•
Optimizer statistics
•
Exadata simulation
•
Guided workflow
